diff --git a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
index f29328c723..754182d5bb 100644
--- a/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Userland/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -695,7 +695,7 @@ Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_se
             }
             return Selector::SimpleSelector {
                 .type = Selector::SimpleSelector::Type::Class,
-                .value = FlyString { class_name_value.token().ident() }
+                .value = Selector::SimpleSelector::Name { class_name_value.token().ident() }
             };
         }
         case '>':
@@ -719,13 +719,13 @@ Parser::ParseErrorOr<Optional<Selector::SimpleSelector>> Parser::parse_simple_se
         }
         return Selector::SimpleSelector {
             .type = Selector::SimpleSelector::Type::Id,
-            .value = FlyString { first_value.token().hash_value() }
+            .value = Selector::SimpleSelector::Name { first_value.token().hash_value() }
         };
     }
     if (first_value.is(Token::Type::Ident)) {
         return Selector::SimpleSelector {
             .type = Selector::SimpleSelector::Type::TagName,
-            .value = FlyString { first_value.token().ident() }
+            .value = Selector::SimpleSelector::Name { first_value.token().ident() }
         };
     }
     if (first_value.is_block() && first_value.block().is_square())
diff --git a/Userland/Libraries/LibWeb/CSS/Selector.h b/Userland/Libraries/LibWeb/CSS/Selector.h
index 4d9a1c0ee2..14ebcdadca 100644
--- a/Userland/Libraries/LibWeb/CSS/Selector.h
+++ b/Userland/Libraries/LibWeb/CSS/Selector.h
@@ -142,8 +142,19 @@ public:
             CaseType case_type;
         };
 
+        struct Name {
+            Name(FlyString n)
+                : name(move(n))
+                , lowercase_name(name.to_lowercase())
+            {
+            }
+
+            FlyString name;
+            FlyString lowercase_name;
+        };
+
         Type type;
-        Variant<Empty, Attribute, PseudoClass, PseudoElement, FlyString> value {};
+        Variant<Empty, Attribute, PseudoClass, PseudoElement, Name> value {};
 
         Attribute const& attribute() const { return value.get<Attribute>(); }
         Attribute& attribute() { return value.get<Attribute>(); }
@@ -151,8 +162,11 @@ public:
         PseudoClass& pseudo_class() { return value.get<PseudoClass>(); }
         PseudoElement const& pseudo_element() const { return value.get<PseudoElement>(); }
         PseudoElement& pseudo_element() { return value.get<PseudoElement>(); }
-        FlyString const& name() const { return value.get<FlyString>(); }
-        FlyString& name() { return value.get<FlyString>(); }
+
+        FlyString const& name() const { return value.get<Name>().name; }
+        FlyString& name() { return value.get<Name>().name; }
+        FlyString const& lowercase_name() const { return value.get<Name>().lowercase_name; }
+        FlyString& lowercase_name() { return value.get<Name>().lowercase_name; }
 
         String serialize() const;
     };
diff --git a/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp b/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
index dfdf426bf8..265b8df8aa 100644
--- a/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
+++ b/Userland/Libraries/LibWeb/CSS/SelectorEngine.cpp
@@ -353,9 +353,9 @@ static inline bool matches(CSS::Selector::SimpleSelector const& component, DOM::
         return element.has_class(component.name());
     case CSS::Selector::SimpleSelector::Type::TagName:
         // See https://html.spec.whatwg.org/multipage/semantics-other.html#case-sensitivity-of-selectors
-        if (is<HTML::HTMLElement>(element) && element.document().document_type() != DOM::Document::Type::XML)
-            return component.name().equals_ignoring_case(element.local_name());
-        return component.name() == element.local_name();
+        if (element.document().document_type() == DOM::Document::Type::HTML)
+            return component.lowercase_name() == element.local_name();
+        return component.name().equals_ignoring_case(element.local_name());
     case CSS::Selector::SimpleSelector::Type::Attribute:
         return matches_attribute(component.attribute(), element);
     case CSS::Selector::SimpleSelector::Type::PseudoClass:
diff --git a/Userland/Libraries/LibWeb/Dump.cpp b/Userland/Libraries/LibWeb/Dump.cpp
index 7b2d642c2b..92e13a5a75 100644
--- a/Userland/Libraries/LibWeb/Dump.cpp
+++ b/Userland/Libraries/LibWeb/Dump.cpp
@@ -372,7 +372,7 @@ void dump_selector(StringBuilder& builder, CSS::Selector const& selector)
 
             builder.appendff("{}:", type_description);
             // FIXME: This is goofy
-            if (simple_selector.value.has<FlyString>())
+            if (simple_selector.value.has<CSS::Selector::SimpleSelector::Name>())
                 builder.append(simple_selector.name());
 
             if (simple_selector.type == CSS::Selector::SimpleSelector::Type::PseudoClass) {